Dicarboxylic acids comprising ten or more carbon atoms can be referred to as long-chain dicarboxylic acids (LCDAs). LCDAs are useful as constituent monomers for various synthetic materials such as polyamides (nylons), polyurethanes, and polyesters. Other uses of LCDAs include, for example, production of certain polycarbonates, powder coatings, fragrances, personal care items, food additives, solvents, cleaning additives, hot-melt adhesives, lubricants, insecticides and fungicides. LCDAs can also be used as plasticizers for engineering plastics and as corrosion inhibitors in metal processing technology, for example.
Quantities of LCDAs suitable for carrying out commercial applications such as described above are generally not found in nature. Certain LCDAs, such as dodecanedioic acid (DDDA), can be prepared via various synthetic processes. However, biological processes such as microbial fermentation could also be useful for producing LCDAs. Feedstocks containing oil or free fatty acids, for example, may be suitable as substrates for fermenting LCDA products. Efforts to ferment LCDAs with yeast biocatalysts have been undertaken (U.S. Pat. Appl. Publ. Nos. 2004/0146999, 2010/0041115, 2013/0267012, 2014/0228586).
Fatty acids can be activated in yeast for use in beta-oxidation and other downstream pathways, thereby drawing fatty acids away from pathways of omega-oxidation. Thus, some yeast biocatalysts have been modified to exhibit reduced fatty acid activation, such as by down-regulating expression of long-chain fatty acyl-CoA synthetase, to augment fermentation of LCDA products via omega-oxidation (e.g., see U.S. Pat. Appl. Publ. Nos. 2014/0228586 and 2013/0267012).
The above disclosures notwithstanding, it has now surprisingly been found that increasing fatty acid activation in yeast by up-regulating long-chain fatty acyl-CoA synthetase allows for high LCDA production. Thus, microbial biocatalysts engineered for high levels of LCDA production are disclosed herein.